Punch in your secret key into this numeric matrix keypad. This keypad has 12 buttons, arranged in a telephone-line 3×4 grid. It’s made of a thin, flexible membrane material with an adhesive backing (just remove the paper) so you can attach it to nearly anything. The keys are connected into a matrix, so you only need 7 microcontroller pins (3-columns and 4-rows) to scan through the pad. Check the tutorials tab for links to an Arduino library and example code.
This 4 Channel Relay Shield is an easy way to control high voltage applications with the Arduino. The maximum switching power for each relay is 70W. You can directly control this shield with the Arduino digital I/Os with an external 9V DC supplty.
DIP switch are very similar to slide switch in terms of functionality. However, DIP switches are made in DIP packages which than can be plugged directly to any standard breadboard!
A solid state relay (SSR) is just what it sounds like; an IC that acts like a mechanical relay. They allow you to control high-voltage AC loads from lower voltage DC control circuitry. Solid state relays, however, have several advantages over mechanical relays. One such advantage is that they can be switched by a much lower voltage and at a much lower current than most mechanical relays. Also, because there s no moving contacts, solid state relays can be switched much faster and for much longer periods without wearing out.
A relay is a switch which can be controlled through a digital signal. This is a board mount DPDT DC mechanic relay. There are 2 separate channels, each channel has NO (Normal Open), COM (Common), NC (Normal Closed) terminals.